Upregulated miR-146a Expression in Peripheral Blood Relates to Th17 and Treg Imbalance in Elder Rheumatoid Arthritis Patients.

BACKGROUND

The expression level of microRNA-146a (miR-146a) increased in peripheral blood and synovialis tissue of rheumatoid arthritis (RA) patient, and it may play an important role in the pathological process of RA. We investigated its possibility as a diagnostic marker and the correlation with T helper 17 (Th17) and Treg cells in elder RA patients.

METHODS

Blood samples were collected from 38 active RA patients, 38 inactive RA patients, and 40 healthy controls. RNA expression levels of miR-146a were detected from the peripheral blood samples. The proportion of Th17 and Treg cells were analyzed, as well as their cell-specific transcription factor retinoic acid-related orphan receptor variant 2 (RORc) and forkhead box protein 3 (FOXP3). Furthermore, secretion of pre-inflammatory and anti-inflammatory factors was detected. Correlations between miR-146a and these factors were also analyzed.

RESULTS

Compared with healthy control, expression levels of miR-146a in inactive and active groups were significantly higher, with the highest level in active group. The expression of miR-146a and the RA severity, Th17 cell ratio, RORc expression, IL-17 level showed a significant positive correlation, while it showed a significantly negative correlation with Treg cell ration, FOXP3 expression, and TGF-β1 secretion.

CONCLUSIONS

These results suggested that miR-146a may be used as a disease progression marker in the peripheral blood of elder RA patients.